IR level sensor or FSR's

[DerStig]

Building a metal max, using a Duet controller. Do I go FSR's or the IR proximity sensor. I use a glass surface and sometimes I use buildtek

[Xenocrates]

If you use multiple bed surface's, I'd use FSR's. Different surfaces and coatings will trigger the IR sensor at different heights, requiring tweaking.

[Jimustanguitar]

You can also do Z probing. http://www.thingiverse.com/thing:1069281" onclick="window.open(this.href);return false;
Another option is an accelerometer mounted to the hotend that can act like a z probe. Hopefully the Eris will be a wild success and there will be kits available to us soon!
A friend build a Pup delta, and it actually mounts the hotend slightly loose and has a snap switch that's triggered that way...

That being said, I'm doing a build right now and I went with FSRs. Betweeen OpenDact and MHackney and 626Pilot's work, I felt like it gave me the best options.